1. Field of the Invention
A first group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film having a high saturation magnetic flux density, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field, and improving a characteristic of a thin film magnetic head.
A second group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film having a high saturation magnetic flux density and a small coercive force, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field, and improving a characteristic of a thin film magnetic head.
A third group of the present invention relates to a soft magnetic thin film, and a thin film magnetic head using the same. More particularly, it relates to a soft magnetic thin film capable of setting a value of a saturation magnetic flux density and a resistance value both at high levels in a well-balanced manner, and a thin film magnetic head using the same.
2. Description of the Related Art
(1) With a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing. In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fexe2x80x94Coxe2x80x94Mxe2x80x94O (M is at least an element selected from Zr and Hf, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is obtained.
However, in the thin film of Fexe2x80x94Co containing oxygen, an increase occurs in an anisotropic magnetic field following increased concentration of oxygen in the film, consequently causing a reduction in permeability of the film.
In order to provide a magnetic film having uniaxial magnetic anisotropy of a proper energy, high electric resistance and saturation magnetization, and a good high-frequency characteristic of permeability, Japanese Patent Application Laid-Open Heisei 5(1996)-273930 discloses an idea of adding various elements to the soft magnetic thin film of Fexe2x80x94Co. Indication is made therein of a possibility of widely containing carbon and oxygen. The disclosed film contains M (at least one selected from Zr, Hf, Nb and Y) as an essential element, and preferable combinations of the elements are described to be a combination of Zr and Si, a combination of Zr and Ge, a combination of Zr and Sn, and a combination of Hf and Si. However, an actually disclosed embodiment sample is only a combination of Zr and Si, and no specific advantages of the contained carbon and oxygen is not made explicit substantially.
(2) As described above, with a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing.
In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fexe2x80x94Coxe2x80x94Mxe2x80x94O or Fexe2x80x94Coxe2x80x94Mxe2x80x94Oxe2x80x94X (M is at least an element selected from the group consisting of Zr and Hf, or a mixture thereof; and X is at least an element selected from the group consisting of Y, Al, Si and B, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is obtained.
However, in the thin film of Fexe2x80x94Co containing oxygen, an increase occurs in an anisotropic magnetic field following increased concentration of oxygen in the film, consequently causing a reduction in permeability of the film.
An example in the related art that may have a relation to the present invention is a soft magnetic alloy disclosed in Japanese Patent Application Heisei 10 (1998)-25530. This soft magnetic alloy, a specific embodiment thereof having a composition of (Co0.72Fe0.28)59Hf16O20C5, was developed to have high specific resistance and permeability in a high-frequency band as a high-frequency magnetic material. Because of a rich content of Co, however, this material has an inconvenience of a low saturation magnetic flux density compared with that of a rich content of Fe.
In order to provide a magnetic film having uniaxial magnetic anisotropy of a proper energy, high electric resistance and saturation magnetization, and a good high-frequency characteristic of permeability, Japanese Patent Application Laid-Open Heisei 8 (1996)-273930 discloses an idea of adding various elements to the soft magnetic thin film of Fexe2x80x94Co. Indication is made therein of a possibility of widely containing carbon and oxygen. The disclosed film contains M (at least one selected from Zr, Hf, Nb and Y) as an essential element, and preferable combinations of the elements are described to be a combination of Zr and Si, a combination of Zr and Ge, a combination of Zr and Sn, and a combination of Hf and Si. However, an actually disclosed embodiment sample is only a combination of Zr and Si, and no specific advantages of the contained carbon and oxygen is not made explicit substantially.
(3) As described above, with a higher recording density of writing on a hard disk recording medium achieved in recent years, progresses have been made in achievements of applying a magnetic head to a narrower track and a higher coercive force of the medium for writing. In a writing head of such a high recording density, in order to generate a sufficient magnetic flux, a material having a saturation magnetic flux density higher than that of permalloy conventionally used for a writing magnetic pole must be used.
An example in the related art that can meet the above-described need is a soft magnetic alloy thin film disclosed in Japanese Patent Application Laid-Open Heisei 5 (1993)-148595. This soft magnetic alloy thin film having a composition of Fexe2x80x94Coxe2x80x94Mxe2x80x94O or Fexe2x80x94Coxe2x80x94Mxe2x80x94Oxe2x80x94X (M is at least an element selected from the group consisting of Zr and Hf, or a mixture thereof; and X is at least an element selected from the group consisting of Y, Al, Si and B, or a mixture thereof) was developed to have a high saturation magnetic flux density, and thermal stability. According to this disclosed thin film, a high saturation magnetic flux density of about 21.0 kG at a maximum is reportedly obtained.
Considering a development of a next-generation head, however, there is no limit to requests for a higher saturation magnetic flux density of a soft magnetic thin film. On the other hand, a value of specific resistance tends to be lowered more as a saturation magnetic flux density is increased more. Therefore, a new thin film composition must be designed, which can secure a desired value of specific resistance, and simultaneously obtain a high saturation magnetic flux density. In other words, it is necessary to design a thin film composition capable of obtaining a desired value of specific resistance while maintaining a value of a saturation magnetic flux density at a high level without any reductions.
The present invention has been made to solve the foregoing conventional problems (1) to (3).
That is, the first group of the present invention is directed to the conventional problem (1), and an object thereof is to solve the problem (1) and provide a soft magnetic thin film having a high saturation magnetic flux density, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field following increased concentration of oxygen, and improving a characteristic of a thin film magnetic head.
In order to achieve the object, the present invention provides a soft magnetic thin film represented by a composition formula of Fealxc2x7Cob1xc2x7Cc1xc2x7Od1. In this case, atomic % values of the a1 to d1 respectively satisfy the following:
51.0xe2x89xa6a1xe2x89xa695.0,
5.0xe2x89xa6b1xe2x89xa649.0
0.5xe2x89xa6c1xe2x89xa610.0
0.5xe2x89xa6d1xe2x89xa620.0
a1+b1+c1+d1=100
The present invention also provides a thin film magnetic head comprising: a magnetic core made of a soft magnetic thin film for forming a loop magnetic circuit; and a magnetic gap formed in a part of the loop magnetic circuit. In this case, the entire or partial soft magnetic thin film of the magnetic core is represented by a composition formula of Fea1xc2x7Cob1xc2x7Cc1xc2x7Od1, and atomic % values of the a1 to d1 respectively satisfy the following:
51.0xe2x89xa6a1xe2x89xa695.0,
5.0xe2x89xa6b1xe2x89xa649.0
0.5xe2x89xa6c1xe2x89xa610.0
0.5xe2x89xa6d1xe2x89xa620.0
a1+b1+c1+d1=100
The second group of the present invention is directed to the conventional problem (2), and an object thereof is to solve the problem (2) and provide a soft magnetic thin film having a high saturation magnetic flux density and a small coercive force, and capable of preventing a reduction in permeability by suppressing an increase of an anisotropic magnetic field following increased concentration of oxygen, and improving a characteristic of a thin film magnetic head.
In order to achieve the object, the present invention provides a soft magnetic thin film represented by a composition formula of Fea2xc2x7Cob2xc2x7M2c2xc2x7Cd2xc2x7Oe2. In this case, the M2 is at least one selected from the group consisting of Ti, V, Ta, Nb, Cr, Mo, W, Cu, Zn, Ga, Al, Zr, Y, Si and B, and atomic % values of the a2 to e2 respectively satisfy the following:
51.0xe2x89xa6a2xe2x89xa695.0,
5.0xe2x89xa6b2xe2x89xa649.0,
0.5xe2x89xa6c2xe2x89xa615.0,
0.5xe2x89xa6d2xe2x89xa610.0,
0.5xe2x89xa6e2xe2x89xa620.0
a+2+b2+c2+d2+e2=100
According to the soft magnetic thin film of the present invention, preferably, the M2 is at least one selected from the group consisting of Zr, Ti, Ta, Nb and Cr.
According to the soft magnetic thin film of the present invention, preferably, the d2 as a carbon content is set to 0.55xe2x89xa6d2xe2x89xa67.0.
The present invention also provides a thin film magnetic head comprising: a magnetic core made of a soft magnetic thin film for forming a loop magnetic circuit; and a magnetic gap formed in a part of the loop magnetic circuit. In this case, the entire or partial soft magnetic thin film of the magnetic core is represented by a composition formula of Fea2xc2x7Cob2xc2x7M2c2xc2x7Cd2xc2x7Oe2, the M2 is at least one selected from the group consisting of Ti, V, Ta, Nb, Cr, Mo, W, Cu, Zn, Ga, Al, Zr, Y, Si and B, and atomic % values of the a2 to e2 respectively satisfy the following:
51.0xe2x89xa6a2xe2x89xa695.0,
5.0xe2x89xa6b2xe2x89xa649.0,
0.5xe2x89xa6c2xe2x89xa615.0,
0.5xe2x89xa6d2xe2x89xa610.0,
0.5xe2x89xa6e2xe2x89xa620.0
a2+b2+c2+d2+e2xe2x89xa6100
The third group of the present invention is directed to the conventional problem (3), and objects thereof are to solve the problem (3), and provide a soft magnetic thin film capable of setting a value of a saturation magnetic flux density and a specific resistance value both at high levels in a well-balanced manner, and a thin film magnetic head using the same.
In order to achieve the objects, the present invention provides a soft magnetic thin film represented by a composition formula of Fea3xc2x7Cob3xc2x7M3c3xc2x7Od3. In this case, the M3 is at least one selected from the group consisting of Ti, V, Ta, Nb, Cr, Mo and W, and atomic % values of the a3 to d3 respectively satisfy the following:
51.0xe2x89xa6a3xe2x89xa695.0,
5.0xe2x89xa6b3xe2x89xa649.0,
0.5xe2x89xa6c3xe2x89xa615.0,
0.5xe2x89xa6d3xe2x89xa620.0,
a3+b3+c3+d3=100
According to the soft magnetic thin film of the present invention, preferably, the M3 is one selected from the group consisting of Ta and Ti.
According to the soft magnetic thin film of the present invention, preferably, ranges of the c3 and d3 in the composition formula of Fea3xc2x7Cob3xc2x7M3c3xc2x7Od3 are respectively set to the following:
0.5xe2x89xa6c3xe2x89xa62.0.
0.5xe2x89xa6d3xe2x89xa68.0
According to the soft magnetic thin film of the present invention, preferably, ranges of c3 and d3 in the composition formula of Fea3xc2x7Cob3xc2x7M3d3xc2x7Od3 are respectively set to the following:
2.1xe2x89xa6c3xe2x89xa64.0,
9.0xe2x89xa6d3xe2x89xa618.0
The present invention also provides a thin film magnetic head comprising: a magnetic core made of a soft magnetic thin film for forming a loop magnetic circuit; and a magnetic gap formed in a part of the loop magnetic circuit. In this case, the entire or partial soft magnetic thin film of the magnetic core is represented by a composition formula of Fea3xc2x7Cob3xc2x7M3c3xc2x7Od3, the M3 is at least one selected from the group consisting of Ti, V, Ta, Nb, Cr, Mo and W, and atomic % values of the a3 to d3 respectively satisfy the following:
51.0xe2x89xa6a3xe2x89xa695.0,
5.0xe2x89xa6b3xe2x89xa649.0,
0.5xe2x89xa6c3xe2x89xa615.0,
0.5xe2x89xa6d3xe2x89xa620.0,
a3+b3+c3+d3=100